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stream standards established for Segment 13B of the Yampa River. Table 20 indicates that • <br />all sites where water quality was analyzed experienced exceedences. Parameters that were <br />higher than the standards include sulfates, sulfides (un-ionized), iron and nitrates. It <br />is noteworthy of mentioning that even Site 11, which is upstream of Seneca II Nine <br />discharges, exceeds the iron end sulfide standards. <br />Pater discharged from the Seneca 11 Mine is not used directly for irrigation. Indirectly, <br />although, water discharged from the mine is significantly diluted by water from either <br />Fish Creek or the Yempe River before it is diverted and used for irrigation. Due fo the <br />relative amount of dilution by additional water from both sources, the ambient water <br />qualities of Fish Creek and the Yampa River ere [he dominant factors in determining their <br />suitability for irrigation. <br />Pater discharged from the Seneca II Mine is used for livestock watering. Table 21 <br />presents the most stringent livestock standards as compiled from various organizations by <br />the OSMRE (OSMRE, 1989). Surface water quality measured at stream and NPDES sites during <br />1993 were compared with the Livestock standards, and the comparison results ere presented <br />in Table 22. pH was measured at higher levels than the livestock standard at three sites. . <br />Aluminum values were also higher than the standard at three sites. <br />As a final note, no exceedences of NPDES effluent criteria (Permit No. CO-0000221) were <br />observed at the outfalls associated with the Seneca II Mine during 1993. <br />Surface Pater Summary. Due to a high snowpack runoff, most NPDES sites had their highest <br />flows that have existed in several years (002 since 1985, 004 since 1984, and 008 for the <br />entire period of record (1988)). Annual average TDS values were higher than their <br />historic ranges at NPDES 002 and Site 2 (due to an increase in high TDS fall bas of lows ), <br />and NPDES 004 and 008 (due to an increase in upgradient mining area and spoil spring <br />discharges). Site 11 had a decrease in its annual average TDS value due to low TDS, high <br />floe snowpack runoff. Annual average TDS values in 1993 fell within their historic ranges <br />at NPDES 003 and Sites 1, 5, 6, 10, 12, and 13. <br />References <br />American Public Health Association (Ed.). 1985. "Standard Methods for the Examination of <br />Pater and Nasteuater", 16th Edition, Nashington, D.C. <br />18 <br />